3-Amino-5-ethyl-6 -methyl-2-pyridone prepn. - from acrylonitrile in 4 stages via new 5-ethyl-6-methyl-2-pyridone, used as intermediate for anti-AIDS agents

摘要

Prepn. of 3-amino-5-ethyl-6-methyl -1H-pyridin-2-one (I) comprises: (a) reacting acrylonitrile with pentan-2-one in presence of catalytic amts. of an acid and an amine to give 5-ethyl-6-methyl-3,4-dihydro -1H-pyrdin-2-one; (b) catalytically dehydrogenating to give 5-ethyl-6-methyl-1H- pyridin-2-one; (c) nitrating with HNO3/H2SO4 to give 3-nitro-5-ethyl-6-methyl -1H-pyridin-2-one and (d) catalytically reducing the nitro gp. with hydrogen. Step (a) is at 200-240 deg.C, in presence of 5-20 mol.% prim. alkylamine or cycloalkylamine and 1-5 mol.% aliphatic carboxylic acid (based on acrylonitrile). Step (b) is effected using a Pd/C catalyst at 170-250 deg.C in presence of a high-boiling solvent. Step (c) is effected with HNO3 and H2SO4 in vol. ratio 1:1-4 at 10-65 deg.C. Step (d) is effected with H2 in presence of Pd/C catalyst. USE/ADVANTAGE - (I) is an intermediate for anti-AIDS agents of formula (V). (I) is obtd. in high yield and purity by a simple, industrial applicable and safe process, avoiding use of potentially explosive nitro cpds.